#define _BSD_SOURCE
#include <sys/stat.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <stdint.h>
#include <sys/sysmacros.h>
#include "syscall.h"
#include "kstat.h"

struct statx {
    uint32_t stx_mask;
    uint32_t stx_blksize;
    uint64_t stx_attributes;
    uint32_t stx_nlink;
    uint32_t stx_uid;
    uint32_t stx_gid;
    uint16_t stx_mode;
    uint16_t pad1;
    uint64_t stx_ino;
    uint64_t stx_size;
    uint64_t stx_blocks;
    uint64_t stx_attributes_mask;
    struct {
        int64_t tv_sec;
        uint32_t tv_nsec;
        int32_t pad;
    } stx_atime, stx_btime, stx_ctime, stx_mtime;
    uint32_t stx_rdev_major;
    uint32_t stx_rdev_minor;
    uint32_t stx_dev_major;
    uint32_t stx_dev_minor;
    uint64_t spare[14];
};

static int fstatat_statx(int fd, const char *restrict path, struct stat *restrict st, int flag)
{
    struct statx stx;

    int ret = __syscall(SYS_statx, fd, path, flag, 0x7ff, &stx);
    if (ret) return ret;

    *st = (struct stat){
        .st_dev = makedev(stx.stx_dev_major, stx.stx_dev_minor),
        .st_ino = stx.stx_ino,
        .st_mode = stx.stx_mode,
        .st_nlink = stx.stx_nlink,
        .st_uid = stx.stx_uid,
        .st_gid = stx.stx_gid,
        .st_rdev = makedev(stx.stx_rdev_major, stx.stx_rdev_minor),
        .st_size = stx.stx_size,
        .st_blksize = stx.stx_blksize,
        .st_blocks = stx.stx_blocks,
        .st_atim.tv_sec = stx.stx_atime.tv_sec,
        .st_atim.tv_nsec = stx.stx_atime.tv_nsec,
        .st_mtim.tv_sec = stx.stx_mtime.tv_sec,
        .st_mtim.tv_nsec = stx.stx_mtime.tv_nsec,
        .st_ctim.tv_sec = stx.stx_ctime.tv_sec,
        .st_ctim.tv_nsec = stx.stx_ctime.tv_nsec,
#if _REDIR_TIME64
        .__st_atim32.tv_sec = stx.stx_atime.tv_sec,
        .__st_atim32.tv_nsec = stx.stx_atime.tv_nsec,
        .__st_mtim32.tv_sec = stx.stx_mtime.tv_sec,
        .__st_mtim32.tv_nsec = stx.stx_mtime.tv_nsec,
        .__st_ctim32.tv_sec = stx.stx_ctime.tv_sec,
        .__st_ctim32.tv_nsec = stx.stx_ctime.tv_nsec,
#endif
    };
    return 0;
}

static int fstatat_kstat(int fd, const char *restrict path, struct stat *restrict st, int flag)
{
    int ret;
    struct kstat kst;

    if (flag==AT_EMPTY_PATH && fd>=0 && !*path) {
        ret = __syscall(SYS_fstat, fd, &kst);
        if (ret==-EBADF && __syscall(SYS_fcntl, fd, F_GETFD)>=0) {
            ret = __syscall(SYS_fstatat, fd, path, &kst, flag);
            if (ret==-EINVAL) {
                char buf[15+3*sizeof(int)];
                __procfdname(buf, fd);
#ifdef SYS_stat
                ret = __syscall(SYS_stat, buf, &kst);
#else
                ret = __syscall(SYS_fstatat, AT_FDCWD, buf, &kst, 0);
#endif
            }
        }
    }
#ifdef SYS_lstat
    else if ((fd == AT_FDCWD || *path=='/') && flag==AT_SYMLINK_NOFOLLOW)
        ret = __syscall(SYS_lstat, path, &kst);
#endif
#ifdef SYS_stat
    else if ((fd == AT_FDCWD || *path=='/') && !flag)
        ret = __syscall(SYS_stat, path, &kst);
#endif
    else ret = __syscall(SYS_fstatat, fd, path, &kst, flag);

    if (ret) return ret;

    *st = (struct stat){
        .st_dev = kst.st_dev,
        .st_ino = kst.st_ino,
        .st_mode = kst.st_mode,
        .st_nlink = kst.st_nlink,
        .st_uid = kst.st_uid,
        .st_gid = kst.st_gid,
        .st_rdev = kst.st_rdev,
        .st_size = kst.st_size,
        .st_blksize = kst.st_blksize,
        .st_blocks = kst.st_blocks,
        .st_atim.tv_sec = kst.st_atime_sec,
        .st_atim.tv_nsec = kst.st_atime_nsec,
        .st_mtim.tv_sec = kst.st_mtime_sec,
        .st_mtim.tv_nsec = kst.st_mtime_nsec,
        .st_ctim.tv_sec = kst.st_ctime_sec,
        .st_ctim.tv_nsec = kst.st_ctime_nsec,
#if _REDIR_TIME64
        .__st_atim32.tv_sec = kst.st_atime_sec,
        .__st_atim32.tv_nsec = kst.st_atime_nsec,
        .__st_mtim32.tv_sec = kst.st_mtime_sec,
        .__st_mtim32.tv_nsec = kst.st_mtime_nsec,
        .__st_ctim32.tv_sec = kst.st_ctime_sec,
        .__st_ctim32.tv_nsec = kst.st_ctime_nsec,
#endif
    };

    return 0;
}

int fstatat(int fd, const char *restrict path, struct stat *restrict st, int flag)
{
    int ret;
    if (sizeof((struct kstat){0}.st_atime_sec) < sizeof(time_t)) {
        ret = fstatat_statx(fd, path, st, flag);
        if (ret!=-ENOSYS) return __syscall_ret(ret);
    }
    ret = fstatat_kstat(fd, path, st, flag);
    return __syscall_ret(ret);
}

#if !_REDIR_TIME64
weak_alias(fstatat, fstatat64);
#endif
